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HUMAN POPULATION DYNAMICS. See World Population Video. Video. What do you think?. Did you Know?. 06_12.JPG. How many people are on Earth?. 6,788,977,211 (6.8 billion) How many people are in the U.S.? 308 million How much is 6.8 billion? See next slide for an exercise. Pop Census.

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## HUMAN POPULATION DYNAMICS

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**See World Population Video**Video • What do you think? Did you Know?**How many people are on Earth?**• 6,788,977,211 (6.8 billion) • How many people are in the U.S.? • 308 million • How much is 6.8 billion? • See next slide for an exercise Pop Census**How long would it take you to put 6.8 billion dots on a**piece of paper? • Take out a piece of paper and pen or pencil. • Count the number of dots you can put on a piece of paper in 5 seconds (have a partner time 5 sec). • Calculate Dots/minute (x12), dots/hour (x60), dots/day (x24), dots/year (x365). • 6.8 billion dots divided by dots/year Note: 77 million more people added per year you were putting dots**How many people are on Earth?**• How much is one billion? • How long is 7.8 billion seconds? • 1 billion seconds is 31 years, 8.5 months! • 6.8 billion = 215 years, 7.5 months!**History of Human Pop Growth**• 1804: 1 billion (took a looong time) • 1927: 2 billion (took 123 years more) • 1960: 3 billion (33 years) • 1974: 4 billion (14 years) • 1987: 5 billion (13 years) • 1999: 6 billion (12 years) • ????: 7 billion (? Years)**World Clock**Current Pop Growth Rate In these 10 seconds… • 10 • 9 • 8 • 7 • 6 • 5 • 4 • 3 • 2 • 1 • 0 • 41 people were born • 18 people died • = 23 people added to Earth During this class… 39,244 born; 17,187 died; 22,058 people added**Current Pop Growth Rate**• 1.15% annual growth • What does this mean? • Use Rule of 70 to determine Doubling Time**Type of Pop Growth**• Exponential Growth: J Curve • Occurs when pop is growing at a percent annual growth (versus some fixed amount).**Power of exponential growth:paper folding example**# Folds Thickness 10 3.9 inches 20 332 feet 30 64 miles 40 65,943 miles 50 67.5 million miles Using 0.0038” for paper thickness (20 lb test) = 263 sheets/inch.**Rule of 70 to determine Doubling Time**• 70 divided by % Annual Growth = Doubling Time (i.e., how long it takes for the population to double)**Rule of 70: Example 1**• Example: 10% annual growth rate • Current population is 1 million • How long will it take to reach: • 2 million? • 70/10 = 7 years • 8 million? • 7 X 3 doubles = 21 years**Rule of 70: Example 2**• Example: 1.15% annual growth rate • Answer: 70/1.2 = 61 years for population to double in size • So… in 61 years, at this rate, we will have twice as many people on Earth!**Exponential Growth**What should be done? http://dieoff.org/page80.htm**Exponential Growth**What should be done? http://dieoff.org/page80.htm**Exponential Growth**What should have been done? http://dieoff.org/page80.htm**Exponential Growth**What should wildlife managers do? Hunt themAdd predatorsMove themDo nothing (let them starve)**Here’s another population**What did you say we should do?**Biotic Potential vs. Environmental Resistance**• One pair of cats adds up to (assumes no deaths): • First yr: 12 • Second yr: 66 • Third yr: 382 • Fourth yr: 2201 • Tenth yr: 80,399,780**Carrying Capacity**• MAXIMUM number of individuals an area can support FOREVER. • Law: Thou shalt not exceed the carrying capacity, for long. • As the caribou found out**Carrying Capacity**• What is the carrying capacity for people on Earth?**Cultural Carrying Capacity**• Maximum number of individuals an area can support forever AT A GIVEN STANDARD OF LIVING. OR**What determines whether a population size changes?**• Rate of Increase = (Birth Rate +Immigration) – (Death Rate + Emigration) • Age Structure =age and sex proportions in a population • Total Fertility Rate = average # of children a woman has in her lifetime. • Replacement Level Fertility Rate = average # of children a couple must have to replace themselves. • 2.1 in MDCs and 2.5 in LDCs**AGE STRUCTURE**Fig. 4.8**Factors affecting birth rates**• Education • Affluence • Religious/cultural norms • Role of women in society • Infant mortality rates • Availability of birth control**What determines whether a population size changes?**• Life Expectancy = how long an individual • is expected to live once they are born.**What determines whether a population size changes?**• Life Expectancy = how long an individual • is expected to live once they are born. • WHAT FACTORS DO YOU THINK • INFLUENCE LIFE EXPECTANCY?**Human Population Growth and the Environment**• Who has a greater impact on the environment? • Lesser Developed Countries?? • More Developed Countries??**Two Types of Overpopulation**• People Overpopulation • Consumption Overpopulation • Who has greater impact on the environment – Lesser Developed Countries with 80% of the people or More Developed Countries using high percentage of the resources?**Questions**• How does population growth affect our world today? • What will happen in the future if we do not control population? • What are the options for controlling population? Pros and Cons: • Volunteer vs Forced • How should we control population?**If we could shrink the earth's population to a village of**precisely 100 people,with all the existing human ratio's remaining the same, there would be: • 57 Asians • 21 Europeans • 14 from the Western Hemisphere, both N and S • 8 Africans • 52 would be female • 48 would be male • 70 would be nonwhite • 30 would be white**If we could shrink the earth's population to a village of**precisely 100 people,with all the existing human ratio's remaining the same, there would be: • 70 would be non-Christian • 30 would be Christian • 6 people would possess 59% of the entire world's wealth and • all 6 would be from the United States

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